Depth Profiling of n‐Type Dopants in Si and GaAs Using Cs+ Bombardment Negative Secondary Ion Mass Spectrometry in Ultrahigh Vacuum

Phosphorus and arsenic ion‐implanted in silicon, and sulfur and silicon ion‐implanted in gallium arsenide have been depth‐profiled by secondary ion mass spectrometry down to concentration limits of ≤ 5 × 10 16 atoms / cm 3 . This was accomplished by monitoring negatively charged secondary ions produced by cesium positive ion bombardment. Contamination from the vacuum system was avoided by performing all analyses at pressures of 4 × 10 − 10 Torr .